olive oil?

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stevenryals

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anyone heard of maintaining yeast activity by adding a bit of olive oil?
 

flyangler18

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Be very careful in doing this, as too much can ruin a batch of beer.

Anecdotally, I've previously experimented with putting a tiny drop of olive oil in my starters in lieu of stirplating them. Very visible yeast growth and activity.

The yeast need sterols to reproduce, which the miniscule drop of olive oil provides.
 

flyangler18

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Just to clarify, oil spoils head retention in beer, so too much will ruin a batch (not to mention any flavor contributions).
We're talking about a very small amount - a single drop per 5 gallon batch.
 

onelegout

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I'm a bit lost here... I may be very new to brewing (only got 2 batches under my belt) but I really can't see a situation where this could be worth trying? I've never had a problem with yeast activity, and surely if your fermentation is stuck you can just raise the temperature and if that doesn't work is it really likely that adding olive oil will? I can understand using this on a high gravity beer if your fermentation completely stops despite raising the temp a little, but the idea of putting it in your starter seems a bit strange to me! Why would you want to chance ruining the flavour profile or head of your beer by adding olive oil to a starter, when the starter will do fine without it?

Can someone explain in which situation this olive-oil trick should be used?

Thanks,
H
 

flyangler18

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I'm a bit lost here... I may be very new to brewing (only got 2 batches under my belt) but I really can't see a situation where this could be worth trying? I've never had a problem with yeast activity, and surely if your fermentation is stuck you can just raise the temperature and if that doesn't work is it really likely that adding olive oil will? I can understand using this on a high gravity beer if your fermentation completely stops despite raising the temp a little, but the idea of putting it in your starter seems a bit strange to me! Why would you want to chance ruining the flavour profile or head of your beer by adding olive oil to a starter, when the starter will do fine without it?

Can someone explain in which situation this olive-oil trick should be used?

Thanks,
H
The technique is somewhat theoretical and esoteric, so I wouldn't yet put it into full time practice. The idea arose from an article written by a brewer at New Belgium who was experimenting with using olive oil for storing yeast - which then became a way for wacky homebrewers to try out new techniques. The science behind this seems to be sound : yeast need sterols for reproduction. Oxygen enables them to metabolize unsaturated fatty acids into their cell walls. By giving the yeast access to sterols present in olive oil, this can be an alternative to oxygenating or otherwise aerating either a starter or an entire batch.
 

conpewter

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The original reason they tried it was to keep beer from getting oxidized. The idea was to keep oxygen out of the beer/wort as much as possible through the whole brewing process. Since yeast need oxygen to produce sterols to help them reproduce they decided to provide the sterols directly and never introduce oxygen to the wort. They didn't get an exact flavor match (which you'll find if you read the thesis) and I'm not sure if the research is continuing on the commercial level.
 

JVD_X

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I'm going to start this thread again... sorry :)

Hasn't a company produced a commercial linolenic acid substitute? Something homebrewers could simply throw into the ferment ala "Yeast Fuel" or whatnot.... it seems all the bickering about olive oil causing head retention issues or how to go about adding minuscule amounts would be moot.
 
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IMHO, it's a lot of crap. Theoretically, olive oil provides some benefit. In reality, pitching a healthy starter (or a proper amount of rehydrated dry yeast) works just fine. In fact, if you overpitch slightly, aeration can be kept to a minimum and fermentation activity will peak very quickly.
 

jason.mundy

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I've been using olive oil in my past 6 batches. My last batch was a Russian Imperial Stout. SG 1.095, FG 1.023 using WLP002.

I mixed water and DME to make a 2L, 1.040 starter.

I then dipped a metal skewer 1/4" into the olive oil and then dipped the skewer in my Erlenmeyer flask prior to the starter boil.

Once cooled, I added my WLP002 yeast and put the flask on a stir plate for 48 hours.

I pitched the entire starter into the five gallon batch.

I let the batch sit in the fermentation chamber for 14 days at 65F.

Reviews of the beer have been good at the LHBC.

I had another brew, same method with olive oil. Scored a 31 in a HB competition.

I have mixed feelings about using the olive oil. I use it because I don't have an oxygen set up. I want to use oxygen because it provides more granular measurements. It is easier to count to 30 with the oxygen turned on, than to dip a wire 1/4" into some olive oil.

It could be everything has been working for me because I've been making an appropriate sized started with a stir plate.

Jason
 

brewzombie

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I have mixed feelings about using the olive oil. I use it because I don't have an oxygen set up. I want to use oxygen because it provides more granular measurements. It is easier to count to 30 with the oxygen turned on, than to dip a wire 1/4" into some olive oil.
Jason
I do the 5 min shake method (I don't have O2), which is a huge pain. I always do starters and adding a drop of oil (or dipping a skewer etc) would be soooo much easier than shaking. I'd love to see some consistent anecdotal evidence or legit research saying the oil method is comparable to aeration as regards traditional homebrewing methods.
 

brewzombie

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Jason: I have a few comments/questions.

I then dipped a metal skewer 1/4" into the olive oil and then dipped the skewer in my Erlenmeyer flask prior to the starter boil.
Prior to the boil...I wonder if boiling can damage the oil molecules. Some others on the forum mentioned adding the oil after boiling...but then what to do about sterilizing it if you didn't boil?

Once cooled, I added my WLP002 yeast and put the flask on a stir plate for 48 hours.
Do you use an airlock or just foil? Since you don't need O2 in your starter, I'm curious if you are aerating the starter plus adding oil. Have you considered a procedure like this?

1. Grow up an aerated starter (e.g. 2L on stir plate w/ foil)
2. Chill and decant off most of the supernatant beer
3. Add the oil (drop or whatever) and resuspend the yeast to mix
4. Let sit for a few few hours while brewing so the oil is taken up by the yeast
5. Pitch into 5 gal non-aerated wort

This way the wort is not aerated, the yeast starter had all the O2 it needed during it's growth phase, and the yeast got a fresh supply of oil to help it deal with growing in the 5 gal of wort. The Grady Hull oil thesis mentioned that adding olive oil doesn't supply the sterols needed for yeast reproduction, just the fatty acids. One of Grady's suggestions was a combo of an aerated starter plus olive oil. See thesis quote below (in italics):

In order to achieve a healthy, vigorous fermentation yeast requires both sterols and fatty acids. In this study only oleic acid [i.e. fatty acids] was provided to the yeast. ... Oxygenating yeast at the beginning of yeast storage may provide the yeast with the sterols necessary for proper fermentation at a time when the yeast is healthy enough to withstand some metabolic activity (Smart 2000). This, together with olive oil addition, may provide the combination of sterols and fatty acids necessary for a proper fermentation. The addition of olive oil and sterols could also be combined with a reduction in wort aeration to achieve a vigorous fermentation with reduced oxygen exposure.
 
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